Self-Healing Robot Muscles Boast Of Uncanny Strength And Flexibility, Yet Cost So Little To Make

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Scientists have developed self-healing robotic muscles that are supposedly capable of impressive feats of strength and flexibility, while also having the ability to perform certain delicate and intricate tasks without any untoward results. And while such contraptions might suggest staggering costs for development, reports hint that they can be manufactured very inexpensively, at about 10 cents per unit.

In a pair of separate studies published in the journals Science and Science Robotics, researchers from the University of Colorado in Boulder explained the processes they used to develop the new contraptions. As explained by Wired, the self-healing, oil-fueled robotic muscles, or actuators, are activated with electricity, and are comparable in strength to human muscles, albeit also capable of far more contractions per second.

The researchers were able to get the robotic muscles to contract and release at such a rapid rate by filling elastic pouches with vegetable oil, with hydrogel electrodes on both sides of each pouch. While it isn’t unusual for actuators to use compressed air or fluids in comparatively large external reservoirs to facilitate movement, there are two things that allow for the quick contracting motions when electricity is applied to the pouches – the specific use of oil inside the flexible pouches, and the fact that long tubes aren’t needed to deliver fluid from a reservoir.

Wired added that the muscles, which are known as hydraulically amplified self-healing electrostatic (HASEL) actuators, come in different designs to correspond to specific tasks and movements. For example, doughnut-shaped actuators allowed a robotic gripper to carefully pick up a raspberry without squishing it, according to Newsweek.

“We draw our inspiration from the astonishing capabilities of biological muscle,” explained University of Colorado-Boulder assistant professor Christoph Keplinger, a senior author on both papers.

“Just like biological muscle, HASEL actuators can reproduce the adaptability of an octopus arm, the speed of a hummingbird, and the strength of an elephant.”

The self-healing ability of the robotic muscles comes from a layer of insulating liquid, which the researchers used instead of the usual solid insulating layers found in other soft robotic actuators. While the latter, more conventional layers may stop functioning if subjected to electrical damage, the liquid layers were described by Newsweek as being more resilient, with the capability to withstand electrical damage and recover immediately. The newly-developed actuators can also sense environmental input like human muscles can, as their electrical features can store potential energy in a capacitor, based on how the actuator is being stretched.


As quoted by Newsweek, UC-Boulder doctoral student Nicholas Kellaris, lead author of the study published in Science Robotics, said that one of the new devices, the Peano-HASEL actuator, has polymer pouches made from the same material used in making potato chip bags. That translates to about 10 cents to construct an individual unit, he added.

“The materials are low-cost, scalable, and compatible with current industrial manufacturing techniques.”

The two new papers represent the second time the field of soft robotics has seen a major breakthrough in recent months. Little more than a month prior to the publication of the twin UC-Boulder studies, scientists from Harvard University and the Massachusetts Institute of Technology drew inspiration from origami to create artificial muscles that can lift about 1,000 times their body weight. As previously noted by the Inquisitr, these robotic muscles showed a lot of promise in addressing the lack of strength previous soft robots had been known for.

Although the new self-healing robotic muscles are similarly promising, there are still a few challenges researchers have to deal with, such as the electricity required to power the artificial muscles. According to UC-Boulder doctoral student Eric Acome, lead author of the Science paper, his team is hard at work on solving the problem of high voltage requirements and has already designed actuators that only use a fifth of the usual voltage.